Researchers turn a laser on the Lady

Science & Technology

April 21, 2002|By NEW YORK TIMES NEWS SERVICE

An uncountable number of photographs have been taken of the Statue of Liberty, but no photo or drawing records the depth of each fold in her gown, the width of her eyes, the curve of each finger clasping her tablet.

The National Park Service, which wants such documentation of Lady Liberty to aid it in making repairs to the huge sculpture, has decided it's time to take such a picture. So it has enlisted researchers at Texas Tech University and a high-tech laser instrument to document the precise shape of the statue's exterior copper skin.

Here's how it works: The researchers, part of Texas Tech's historic preservation program, set up their equipment at the base of the statue. The instrument fires a laser pulse at the statue, and measures the time it takes the pulse to reflect back, less than a millionth of a second later.

The instrument then rotates its direction slightly, firing another pulse at a neighboring point, and so on, scanning a swath of the statue's surface.

The data gathered on the torch-holding arm are a bit fuzzy. Buffeted by 15-mile-an-hour winds, the arm swayed back and forth a couple of inches during the scans.

The researchers hope to return this summer to take more scans from the top of the pedestal, to capture the shape of Liberty's feet. Data obtained by other techniques from a helicopter will probably be needed to fill in the top of the crown and other gaps.

"It's not an X-ray machine," said Glenn E. Hill, a professor of architecture at Texas Tech who is involved in the project. "It can't go through things."

Once the famous statue is completely mapped, the researchers plan more scans of historic structures, including Hearst Castle in California and the ruins of a complex of the ancient Anasazi people in New Mexico.